Gas cap ?

[kwb]

I have a vented /unvented cap. does the selector point to the position I want or is it opposite? thanks

[svramselaar]

hi

if you turn the spring and it hangs loose gap is vented

[kwb]

Thanks for the reply svramselaar. The reason I ask about the position of the vent spring is, pressure would build up in the tank regardless of the spring location. It's a new cap but not an oem. when I turn it to open the vent valve still had tension, so I bent the tabs just enough to let the valve free. I have 3/4 tank of fuel, so I'll drive it a few miles today and check for pressure. thanks. Ken

[kwb]

I guess the cap is junk. tank still builds pressure

[svramselaar]

Hi
There must be also a ventline from the tank to the aircleaner
If there is a fordingkit it sites at a T near the brake cyll cap

[kwb]

Hi!
I checked the T fitting on the air filter, it is free flowing. From the T fitting there is a vacuum line to the fuel pump safety switch and a 3/16 line to the vent on the fuel pump housing. maybe the vent on the pump housing could be stuck?

[rickf]

The vent on the fuel pump is only to vent the pump in case the pump diaphragm fails. And to let air into the upper section of the pump. The line from the tank to the air cleaner is to let air go from the air cleaner into the tank to prevent a vacuum as gas is drawn from the tank. There is a one way valve in the tank end of that vent that does not allow pressure to go from tank to air cleaner so I have been told. But in fording systems there have been cases of the brake fluid being contaminated with gasoline so it must happen.

[kwb]

Hey rickf
I have an electric in tank fuel pump. If the gas cap is venting the fuel tank should be natural?

[rickf]

The tank should not have pressure or vacuum. In a closed emissions system this is all handled by the emissions controls and in the older systems it is handled by the gas cap and the vent line to the air cleaner.

[kwb]

Looks like I need to get another cap.

[Mark]

Gas cap, pointing to open

[Mark]

Gas cap M151A2.png

[kwb]

This is the seconded gas cap, and both won't vent. starting to think that when the inner part was assembled to the outer there is no space to vent even when the lever is set to vent?

[kwb]

Pressure in gas tank solved! I have two new gas caps and decided to tinker with one of them. I removed the gasket and drilled a 1/16'' hole in the corner of the cap through just one layer. I drilled it at the12 o'clock position. I did not drill through gasket tension ring. works good

[kwb]

Hi Mark!
Thanks for the pictures. I was sure the selector should point to what you want but when it made no difference on open or close, I just thought I needed to start asking questions.